Maine BMV CDL General Knowledge Practice Test 10

  • Questions50
  • Correct to pass40
  • Passing score80%
  • Minimum age16 years

Minimum age: 16 years to operate a commercial motor vehicle, 21 years for a bus or hazardous materials

50 questions. Pick an answer to see if it is right and why; you need 40 correct answers to pass.

  1. 1. On a scale, your loaded truck is well under the gross weight limit, but one axle is above the limit for that axle. What does this mean?

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    Answer D: The vehicle is overloaded and the load must be shifted or reduced before you drive on

    Each axle and axle group has its own limit and each must be respected; being under the gross limit does not excuse an overloaded axle.

  2. 2. Which parts of total stopping distance can a driver shorten simply by staying alert and looking far ahead?

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    Answer B: Perception distance and reaction distance

    Alertness shortens the time spent recognizing a hazard and moving your foot to the pedal; braking distance depends on speed, weight, brakes and the road surface.

  3. 3. What should you look for on the electrical wiring in the engine compartment?

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    Answer A: Worn, frayed or cracked insulation and loose or corroded connections

    Damaged insulation can short a circuit against the frame or engine, which can kill a lamp you depend on or start a fire.

  4. 4. Why should the radiator cap never be removed while the engine is hot?

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    Answer A: The cooling system is under pressure and scalding coolant can be sprayed out

    A hot cooling system holds pressurized coolant above its normal boiling point, so releasing the cap can throw boiling liquid and steam at whoever is holding it.

  5. 5. When is tire pressure most accurately compared with the recommended figure?

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    Answer B: When the tires are cold, before the vehicle has been driven

    Recommended pressures are cold pressures, so a reading taken before the tires have heated up is the only one that can be compared directly.

  6. 6. Why should both outside mirrors be checked over and over while backing?

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    Answer B: Each mirror covers only part of the path and neither covers the blind spots, so people and objects can appear without warning

    Working both mirrors in turn is the only way to follow the whole path of a vehicle you cannot see behind.

  7. 7. What is the purpose of blocking placed against cargo on a trailer deck?

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    Answer B: To fill the space around the cargo so it cannot slide

    Blocking is shaped to fit snugly against the cargo and fastened to the deck, removing the room the load would need in order to move.

  8. 8. A straight truck has a long body behind the rear axle. What happens to that overhang in a sharp left turn?

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    Answer D: It swings out to the right and can strike a vehicle or an object on that side

    Body that hangs behind the rear axle swings the opposite way to the turn, so the tail of the truck sweeps out into the next lane or over the curb.

  9. 9. At a rest area you find that the load has shifted although the straps still feel tight. What should you do?

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    Answer C: Correct the load before driving on, since a shifted load is no longer secure

    Movement means the securement has already failed once, and a load that has shifted can shift again, so it is put right before the vehicle moves.

  10. 10. Which lights should be used in fog, by day or by night?

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    Answer A: Low beams and fog lights, together with the four-way flashers

    High beam light bounces back off the water droplets and makes seeing worse, while low beams, fog lights and flashers help you see and help others see you.

  11. 11. Which factors determine a safe speed for a long, steep downgrade?

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    Answer C: The steepness and length of the grade, the weight of the vehicle and cargo, and the road and weather conditions

    Gravity, weight and traction all decide how fast a heavy vehicle can safely descend, which is why signs often post lower speeds for trucks on grades.

  12. 12. How is the fluid level in an automatic transmission usually checked?

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    Answer A: With the engine running, following the procedure in the operator manual

    Most automatic transmissions are designed to be checked with the engine running, and the operator manual gives the exact conditions for that vehicle.

  13. 13. The car in the next lane still has snow covering most of its windows. What should you assume?

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    Answer C: That driver cannot see you and may move into your lane

    A driver whose view is blocked cannot see the vehicles around, so you should assume you are invisible and stay out of that vehicle path.

  14. 14. You are hauling a sealed trailer and have been told in writing not to open it. How does that affect the en route cargo checks?

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    Answer C: You do not have to inspect the cargo itself, but the vehicle and weight are still yours

    The en route cargo inspection rule does not apply to a driver of a sealed vehicle who has been ordered not to open it, but every other responsibility, including legal weight, remains.

  15. 15. You have chosen 40 miles per hour as your safe speed for a downgrade. How should the brakes be used?

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    Answer A: Brake firmly to about 35, release, and repeat at 40

    Proper technique is firm application to about 5 miles per hour below the safe speed, then full release so the brakes cool before the next application.

  16. 16. During a stop you find a package in the trailer leaking an unknown chemical. What should you do?

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    Answer C: Keep clear, keep others away and get help without touching the package

    A driver without the training and equipment does not handle a leak; the job is to protect people from the material and get qualified help to the scene.

  17. 17. On the Interstate System, what are the federal maximums for a tandem axle group and for gross vehicle weight?

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    Answer B: 34,000 pounds and 80,000 pounds

    The federal Interstate limits allow 34,000 pounds on a tandem axle group and 80,000 pounds gross.

  18. 18. What does gross vehicle weight mean, as opposed to gross vehicle weight rating?

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    Answer B: The actual weight of the single vehicle plus everything it is carrying

    Gross vehicle weight is what the vehicle actually weighs at that moment; the rating is the maximum the manufacturer allows it to weigh.

  19. 19. You pick up a sealed trailer at a shipper. What should you check before leaving the dock?

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    Answer B: That the seal number matches the paperwork and that the doors are properly closed

    You cannot look at a sealed load, but you can confirm that the seal is intact, that its number matches the documents and that the doors are secure.

  20. 20. You have finished a lane change in a vehicle whose turn signal does not cancel by itself. What must you do?

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    Answer D: Turn the signal off yourself

    A signal left running tells other drivers you are about to move again, and they may act on that false information.

  21. 21. Why should a driver avoid traveling alongside another vehicle for any length of time?

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    Answer D: You lose your escape route and you may be sitting in the other driver blind spot

    Running beside someone leaves nowhere to move if you have to change lanes, and the other driver may not know you are there at all.

  22. 22. The combined working load limit of the tiedowns on a load must equal at least what share of the cargo weight?

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    Answer C: One half of the cargo weight

    Federal securement rules set the aggregate working load limit at no less than half the weight of the article or group of articles being held.

  23. 23. When must a post-trip inspection be made?

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    Answer D: At the end of each day the driver operates the vehicle

    The post-trip inspection closes out each driving day so that anything found is recorded before the vehicle is handed to the next driver.

  24. 24. Which vehicles are most likely to get hung up on a raised railroad crossing?

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    Answer A: Low-slung units such as car carriers and lowboys

    Vehicles with low ground clearance or a long wheelbase can bottom out on a humped crossing and become stuck on the tracks.

  25. 25. When is a road surface usually most slippery during a rain shower?

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    Answer A: Just after the rain starts, when water mixes with oil and dirt on the surface

    The first rain lifts oil and dust into a slick film that has not yet been washed away, so the road is more slippery than it will be later.

  26. 26. Which document must be available to show that the annual inspection was carried out?

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    Answer C: The inspection report or a copy of it, or a decal displayed on the vehicle

    Proof of the periodic inspection travels with the vehicle, either as the report itself or as the decal fixed where an inspector can see it.

  27. 27. Cargo carried inside the cab must never do which of these?

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    Answer C: Block the driver view, restrict arm or leg movement, or block an emergency exit

    Anything inside the cab must leave the driver a clear view, free movement of the arms and legs, and an unobstructed way out of the vehicle.

  28. 28. What are you checking when you pull the engine oil dipstick during the pre-trip?

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    Answer A: That the oil level is within the safe operating range marked on the stick

    The dipstick shows whether there is enough oil to lubricate and cool the engine, and a level outside the safe range must be corrected before driving.

  29. 29. What condition should the fifth wheel be in before you back under a trailer?

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    Answer C: Jaws open, plate greased, and the fifth wheel tilted down toward the rear

    The jaws have to be open to take the kingpin, the plate must be lubricated to prevent hard steering, and the fifth wheel is tilted down at the rear so the trailer apron can ride up onto it.

  30. 30. When a helper guides you while backing, what should be agreed on before you start?

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    Answer D: A set of hand signals, especially the signal that means stop

    The driver and helper must agree on signals in advance, above all the stop signal, because they usually cannot hear each other.

  31. 31. What are you looking for on the brake drums during the walkaround?

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    Answer B: Cracks, dents and any oil or grease that has reached the friction surface

    A cracked or badly scored drum can break apart under braking heat, and oil or grease on the friction surface destroys the braking effort at that wheel.

  32. 32. What are you checking on the mud flaps during the walkaround?

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    Answer C: That they are securely attached, not torn and not dragging on the ground

    A flap that is torn or hanging loose stops shielding following traffic from spray and stones, and a dragging flap can catch and tear away on the road.

  33. 33. You hear air escaping from a trailer tire during the pre-trip. What should you do?

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    Answer C: Have it repaired or replaced before the vehicle is driven

    An audible leak means the tire is failing now, and federal rules do not allow a vehicle to be operated on a flat or leaking tire.

  34. 34. What are the rules for using your turn signal before a turn or lane change?

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    Answer A: Signal early, keep the signal on until the turn is finished, then cancel it

    An early, continuous signal tells others what you plan to do; cancelling afterward keeps the signal from misleading them.

  35. 35. You must drive well below the speed of surrounding traffic, for example when climbing a steep grade with a heavy load. What should you do?

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    Answer B: Turn on the four-way flashers to warn following traffic, where state law allows it

    Flashers warn faster traffic that a slow-moving vehicle is ahead, which helps prevent rear-end crashes; some states restrict their use while moving, so check the local rule.

  36. 36. What is the correct way to make a right turn in a long vehicle?

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    Answer D: Keep the rear of the vehicle close to the curb and swing wide only as you complete the turn

    Swinging left before a right turn invites another driver to move into the gap on your right, so any extra width is taken as the turn is finished.

  37. 37. How often must every commercial motor vehicle receive a periodic inspection?

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    Answer C: At least once every twelve months

    Federal rules require each commercial motor vehicle to pass a periodic inspection at least once in every twelve month period.

  38. 38. A dock crew loads all of the freight at the very back of a 48 foot van trailer. What are the two consequences?

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    Answer A: The steering axle is relieved of weight and steering becomes light, and the trailer axles may go over the limit

    Weight placed far to the rear lifts weight off the front of the combination, so the steering goes light while the trailer axles take too much of the load.

  39. 39. You are stopped in a line of traffic behind a car. How much space should you leave in front of you?

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    Answer C: Enough to see where the rear tires of that car meet the road

    That amount of space lets you pull around the vehicle ahead if it stalls and absorbs some of the shock if you are struck from behind.

  40. 40. What are you looking for when you check the drive belts in the engine compartment?

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    Answer C: That each belt is snug and free of cracks, frays or heavy wear

    A loose or cracked belt can break and stop the fan, the water pump or the alternator, which leads quickly to overheating or a dead electrical system.

  41. 41. What is checked about the engine cooling system during the engine compartment inspection?

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    Answer C: That the coolant level is adequate and the radiator and hoses are not leaking

    A low coolant level or a leaking hose leads to overheating, which can stop the vehicle in a place where stopping is dangerous.

  42. 42. You are loading lengths of large diameter pipe on a flatbed. What is needed besides the tiedowns?

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    Answer D: Chocks, wedges or cradles that keep the pipe from rolling

    Anything that can roll must be prevented from rolling by chocks, wedges, cradles or a similar device that is itself secured so it cannot come out.

  43. 43. Two tires in a dual set have noticeably different diameters. Why is that a problem?

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    Answer C: The larger tire carries more than its share of the load and can be overloaded

    The taller tire touches the road first and takes most of the weight, so it runs overloaded and hot while the smaller one does little work.

  44. 44. What speed and gear should be used when backing a large vehicle?

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    Answer B: As slowly as possible, in the lowest reverse gear

    Backing slowly in the lowest reverse gear keeps the vehicle under precise control and leaves time to correct the path.

  45. 45. You are drifting in the lane, yawning constantly and cannot remember the last few miles. What is the only reliable cure?

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    Answer C: Stopping in a safe place and sleeping

    Those are classic drowsiness warning signs, and nothing except sleep repays the sleep the body is missing.

  46. 46. During the walkaround inspection, where does the driver normally start and how does the check proceed?

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    Answer C: At the left front of the vehicle, working around it in a set order that returns to the cab

    The walkaround follows the same route every time, starting at the left front and circling the vehicle, so that nothing is skipped when the driver is tired or rushed.

  47. 47. Which components on a typical engine are driven by belts that must be checked for wear and tension?

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    Answer D: The alternator, the water pump and, on many vehicles, the air compressor

    Belts drive accessories such as the alternator, the water pump and the air compressor, so one failed belt can take out charging, cooling or air supply.

  48. 48. What does the driver check in the final step of the seven-step inspection?

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    Answer A: Hydraulic brake leaks where those brakes are fitted, then the parking brake and the service brakes

    The last step is done with the engine started: test for hydraulic leaks on vehicles with hydraulic brakes, then prove that the parking brake holds and that the service brakes stop the vehicle.

  49. 49. How much sleep does a typical adult driver need each day to stay properly alert?

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    Answer D: Seven to eight hours

    Most adults need seven to eight hours of sleep in every 24 hours, and a driver who regularly gets less builds up a debt that shows up behind the wheel.

  50. 50. How does a load carried high in the trailer affect safe speed through a curve?

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    Answer B: It raises the rollover risk, so the speed must be lower

    A high center of gravity lets the vehicle tip long before the tires lose their grip, so height of the load directly limits curve speed.